Will Laser Blasters Ever Be Possible?
Video lesson + interactive tasks about lasers, how laser beams work, and why sci-fi laser weapons are still mostly impossible.
Stage 1
GLOSSARY
Before watching, review the words that will help you understand the video.
- laser beam — a very thin and powerful beam of light made by a laser
- photon — the smallest unit (particle) of light
- wavelength — the distance between two peaks of a wave of light
- stimulated emission — when an excited particle releases light and creates another identical light particle
- monochromatic — consisting of only one color of light
- coherent — moving together in the same direction and in the same pattern
- barcode — black and white lines that a scanner reads to get information about a product
- precision — the ability to be very exact and accurate
- scatter — to spread in many different directions
- fragile — easily broken or damaged
Stage 2
PREDICTION
Using the new words, choose the most likely topic of the video.
1) What will the video most likely explain?
Stage 3
FIRST WATCH — Listening for Gist
Watch the video once. Do not pause the video. Focus on the general idea.
1) Choose the best summary of the video.
Stage 4
SECOND WATCH — Listening for Details
Watch the video again. Focus on details. You may pause if necessary.
True / False
1) The video says that laser eye surgery and laser cutters show that lasers can already affect real materials.
2) Ordinary light travels in one exact direction and has only one wavelength.
3) Laser beams are generated through a process called stimulated emission.
4) The video says lasers are useless for carrying information.
5) Heat and the atmosphere can limit how powerful or effective laser weapons can be.
Multiple Choice
1) What is ordinary light like, according to the video?
2) What happens during stimulated emission?
3) Why are laser beams good for carrying information?
4) Why do laser beams have destructive potential?
5) What is one reason blasters remain mostly science fiction?
Stage 5
VOCABULARY PRACTICE
Task 1
Match the word and the picture
Tap a word, then tap an image. Listen and pronounce.
Task 2
Match the word and the definition
Tap a word, then tap the correct definition. Wrong answers won’t be placed.
Task 3
Fill in the gaps
Tap a word, then tap a gap. Wrong answers won’t be placed. Tap a filled gap to clear it.
Stage 6
FINAL VOCABULARY TEST (Score)
Complete the final test. Click Submit & Score.