Transcript Do you think light has a family?

Core Physics – Energy
Exam Date -
“Slip, slop
slap”
L/O :- To understand the dangers of
electromagnetic radiation
Quick Quiz - What do you remember
from last lesson?
• Write out the electromagnetic spectrum from longest to
shortest
• What is the law of reflection?
• What is the equation for working out the speed of a wave?
• What happens to a light ray when it travels from air
through glass? Why does this happen?
• What is diffraction?
• What are the 2 different types of wave? Give an example
• How do you work out the pay-back time for insulation?
• What are the pros and cons of wind energy?
• How does increasing the volume of a sound affect the
wave?
What do you think caused all of these?
The Electromagnetic Spectrum
Each type of radiation shown in the electromagnetic spectrum has a
different wavelength and a different frequency:
High frequency,
_____ wavelength
Gamma
rays
X-rays
Low frequency, _____
(high) wavelength
Ultra violet
Visible
light
Infra red
Microwaves
Radio/TV
γ
The shorter wavelengths and
higher frequency wavelengths can
cause the cells to MUTATE. This
can lead to CANCER
Which of these
are the most
dangerous?
What affects
how dangerous
the wave is?
What part of the electromagnetic spectrum
causes all of these types of cancer?
What can you
do to help
prevent all of
these?
Do In the UK really need to
worry about the sun??
Use the articles to answer these questions
• Give 2 things, other than skin cancer that exposure to the sun
can cause
• What are the 2 types of rays from the sun that can cause skin
cancer?
• Name 3 things that you should do to prevent UV skin damage?
• Give 4 possible warning signs of skin cancer?
• What is it most important thing to look for in a sun cream?
• What is the UV index?
• When is it most important to stay out of the sun?
• What type of skins are most likely to be affected by skin
exposure?
• What has lead to an increase in the UV rays reaching us from
the sun in the last 15 years?
Journalist Cornelia Dobb knew about the dangers of tanning; she'd even done a feature on skin cancer, but
she never really imagined it would affect her. Here she tells her story.
It looked like a beauty spot, perhaps a little blacker than its neighbours, but it certainly didn't look like a killer.
It had been there for just over a year, although I had no recollection of when it first appeared.
It didn't change shape, size or colour, nor did it bleed or itch, so I put it to the back on my mind.
A year later, I was sitting chatting to my GP about malaria tablets. I was about to move to Cambodia for two
years with my husband-to-be, a BBC correspondent. It was a hot summer's day and I sat cross-legged with one
bare foot resting on the opposite thigh. 'Do you know you have moles on the soles of your feet?' she interrupted.
She sounded alarmed. 'Yes', I said. 'I've had them for years. I've got them on the palms too, but they're not
doing anything they shouldn't.'
She seemed satisfied that there was nothing to worry about, and returned to the more pressing matter of
malaria and rabies. Up against life-threatening diseases contracted from mosquitoes, bad water, pigs and mad
dogs the sun didn't seem to pose much of a threat.
A couple of weeks later, I received a letter from that same GP. 'I've changed my mind about those moles,' it
said. 'Given that you're about to move to the tropics, I'd definitely get them checked out.' With incredible
efficiency, she had even booked me an appointment. I looked at the date: 4pm, 22 July 1994 - less than 24 hours
before I was due to walk down the aisle in a Dorset church. I cancelled the appointment.
After our honeymoon, my husband, Jonathan, left almost immediately for his new posting in Cambodia. I would
join him when I had organised the letting of the house and packed everything up. There were so many loose ends
to tie up; I had lists of things to do. At the bottom of my health checklist was (if I get time) to re-book that
appointment at the Chelsea & Westminster Hospital dermatology department.
Somehow, I did get time. I went along a couple of weeks before I was due to get on the plane to Cambodia. The
consultant checked my feet and hands and told me not to worry about them: they looked perfectly harmless.
Just as I thought. I was walking out of the door. I stopped and said, 'Just before you go, would you mind taking a
look at this one on mu tummy?
The dermatologist told me to come back that afternoon to have it removed. It wasn’t the response I had
expected or wanted. It was inconvenient, now I had to hang around all day.
Grumpily, I returned to the ward, was ushered into a treatment room and on to the bed. My tummy was numbed
with a local anesthetic and then a little eye-shaped patch was carved out of it and popped in a jar. The hole left
behind required one stitch and that was it. They said they'd contact me if there was any problem with it, but if
not, bon voyage! I didn't expect to hear from them again.
A week later, with packing boxes all around me and tenants due to move in any minute, there was a message on
the answering machine. The voice was matter-of-fact. I had a Malignant melanoma.
I didn't hear anything else. It was cancer; it was fast; it was uncontrollable and probably deadly. I had got it.
Would I die? 'Someone’s looking after you,' said the voice on the other end of the phone. 'If you hadn't
discovered this by now, it's unlikely that you would have made it back from Asia.'
I returned to the dermatology ward the following morning. This time, I didn't resent the hanging around; I was
brimming with gratitude that they had found this thing. I went to the same little room with the same kind
Scottish nurse. There was much more anesthetic this time, several injections, and the area they cut was broader
and deeper. They needed to do a biopsy to see if the melanoma had spread downwards. I left with eight stitches
where a week before there had been just one. I would have to wait ten days to know if the cancer had spread.
That night I went to bed feeling incredibly alone with my uncertainty and fear. I couldn't sleep. I sat bolt
upright in the middle of the night, put the light on and started poring over every freckle, imagining that it was
sending cancerous cells into my bloodstream. I recounted in my mind all those holidays to Spain, France and
Greece in my teens and 20s, when the thing to do was to burn yourself for the first couple of days to get that
golden tan going and then have it all peel off on the plane home. I'd been trekking in Thailand with no protection,
arguing in my head that I wasn't lying on a beach, therefore I couldn't burn. I'd hitchhiked my way around
Australia with a bottle of SPF4. It was all my fault.
I had been incredibly lucky. The melanoma was in situ, on the surface, and hadn't spread. I had been saved. It
felt as though somebody, somewhere had been watching over me. I could so easily have not made it to the
hospital. I could so easily have walked out the door without mentioning the mole on my stomach. I could have gone
to Cambodia, still a sun worshipper. I could have died.
Three years on, and I'm still a little paranoid about new moles appearing. I'll suddenly get fixated with one
particular mole and it'll bother me for weeks until I get a specialist to check it out. I feel like I'm on a mission
now when I see red bodies splayed out by a pool, roasting themselves in oil under the midday tropical sun. I have
an overwhelming urge to tap them on the blistering shoulder and warn them, because, until three years ago, I was
just like them.
I still love the feeling of sunshine on my face and I haven't quite managed to convince myself that pale is
beautiful. But I know now that when I'm tanned, I might look and feel healthier for a couple of weeks, but in the
long run, I'm actually risking my life.
Task - Design a poster / TV advert to
explain how people can protect
themselves against UV radiation
What have you learnt?
• Do you know which are the most dangerous UV
rays
• Can you explain how high frequency
Electromagnetic waves affect your cells?
• Can you give 2 ways you can protect yourself
against harmful UV radiation from the sun?