🧪 Chemistry
What is the smallest particle of an element that retains its chemical properties?
Atom
Which organelle controls the activities of a cell?
Nucleus
What force pulls objects toward the Earth?
Gravity
What do the three environmental Rs stand for?
Reduce, Reuse, Recycle
My famous equation E = mc² describes the relationship between mass and energy. Who am I?
Albert Einstein
What gas is produced when magnesium reacts with dilute hydrochloric acid?
Hydrogen
Which blood cells transport oxygen around the body?
Red blood cells
What type of energy is stored in a stretched elastic band?
Elastic potential energy
Which greenhouse gas is released in large amounts when coal, oil and natural gas are burned?
carbon dioxide
Why can astronauts communicate using radio waves in space but cannot communicate by shouting directly to one another?
Radio waves can travel through a vacuum; sound cannot.
An atom has 12 protons and 10 electrons. What is its charge?
+2
Which process causes water to move across a partially permeable membrane from higher to lower water potential?
Osmosis
Which electromagnetic radiation is commonly used in TV remote controls?
Infrared.
What term describes the variety of species living in an ecosystem?
Biodiversity
If you could travel to the Moon, your mass would stay the same but your weight would change. Would your weight increase or decrease, and why?
Decrease — the Moon has a weaker gravitational field.
A solution changes from pH 2 to pH 4. How many times lower is its hydrogen ion concentration?
100 times
A person touches something very hot and pulls their hand away before consciously deciding to do so. What type of response is this?
Reflex action
Why can a person sometimes see lightning before hearing the thunder produced at nearly the same time?
Light travels much faster than sound
Coal, oil and natural gas are collectively known as what?
Fossil fuels
Which scientist proposed the theory of natural selection through evolution?
Charles Darwin
A piece of reactive metal is stored under oil because exposure to air or water could cause a rapid reaction. Which Group I family does this metal belong to?
Alkali metals
Which process allows nitrate ions to enter root hair cells even when their concentration is lower in the soil than inside the cells?
Active transport
You stand in front of a plane mirror and raise your right hand. Your image appears to raise its left hand. What property of a mirror image explains this?
Lateral inversion
I am the process in which nutrients enter water, algae grow rapidly, light penetration falls, decomposition increases and dissolved oxygen decreases. What am I?
Eutrophication
What process converts atmospheric nitrogen into nitrogen-containing compounds that plants can eventually use?
Nitrogen fixation